It seems when you gain victory rush your general combat goes up but when you return to normal you get a negative (red) general combat stat that doesnt go away.
This was a general issue with any effects that change skills by a percent, and should now be fixed. Please post if it crops up again.
[#GMCHAT] <Mirazia> I think you're enjoying this [mighty winter stuff] more than you realised
[#GMCHAT] <Rias> I AM AND IF THAT'S WRONG I DON'T WANT TO BE RIGHT